1. Field of the Invention
This invention relates to a stable and reliable nonaqueous electrolyte secondary cell having a high energy density and an extended charge/discharge life.
1. Prior Art
In the prior art, a number of proposals were made for high energy density cells. Lithium cells using lithium as a negative electrode active material and fluorinated graphite or manganese dioxide as a positive electrode active material have been marketed. These cells are primary cells which cannot be recharged.
One example of secondary cells using lithium as a negative electrode active material is non-aqueous electrolyte secondary cells using vanadium oxide (V.sub.2 O.sub.5) in the positive electrode as proposed, for example, in Japanese Patent Application Kokai No. 48-60240 and W. B. Ehner and W. C. Merz, Roc. 28th Power Sources Symp., June 1978, page 214.
These cells using metallic lithium as a negative electrode usually suffer from the problem that dendrite generates or the negative electrode is pulverized during charging. The cycle performance of the cell is fairly improved by using a lithium-aluminum alloy instead of metallic lithium as the negative electrode. The lithium-aluminum alloy, however, is too poorly flexible to apply to cylindrical cells having a spiral electrode structure.